The new horizons of advanced imaging, especially in oncology, must increasingly consider not only diagnostic efficacy but also sustainability for patients, prize-winning researchers told ECR 2025 delegates.
In an e-poster exhibit at the Vienna congress, Andrea Masperi and Cristiano Michele Girlando of the European Institute of Oncology in Milan presented the findings of a study that aimed to evaluate energetically and biologically sustainable diagnostic lines for patients with metastatic breast cancer (MBC). They received a magna cum laude award from ECR 2025 judges.
Although the most common site of MBC is bone, there is currently no standardized imaging modality that offers accurate assessment of bone treatment response, Masperi and Girlando explained. CT is a standard method for evaluating MBC, but it has limitations in assessing bony metastases. RECIST 1.1 criteria classify bone lesions as nonmeasurable unless there is measurable soft tissue involvement. CT struggles with qualitative assessment, especially for stable lesion sizes or sclerotic responses.
FDG-PET/CT provides functional insights by detecting metabolic changes before structural alterations, making it valuable for therapy response monitoring, but it has limitations in visualizing metabolically silent bone metastases, according to Masperi and Girlando.
"Whole-body MRI is emerging as a superior tool for assessing bone marrow and monitoring therapy response in advanced breast cancer. It can detect progressive disease in cases missed by other modalities, demonstrating its potential to guide treatment decisions effectively," they noted.
Additionally, modalities like MRI, CT, bone scans, and PET-CT are significant contributors to greenhouse gas emissions, with radiology accounting for approximately 1% of global healthcare-related emissions. To mitigate these effects, low-energy imaging techniques should be prioritized without compromising diagnostic accuracy.
"Whole-body MRI presents an opportunity for sustainable and patient-friendly diagnostics, combining high efficacy with reduced environmental and biological impacts," the researchers added.
Study logistics
The Milan study aimed to quantify the energy consumption and greenhouse gas emissions associated with imaging modalities, identifying the most sustainable and beneficial approach for patients with MBC. The analysis might help to establish a model for balancing clinical and environmental priorities in radiology departments globally.
The researchers analyzed 78 patients (median age: 57 years, range 32-81 years) who participated in a diagnostic protocol between September 2019 and July 2023. All patients underwent whole-body MRI (Diagnostic Line 1, DL1) and one of the two reference diagnostic pathways: FDG-PET/CT (Diagnostic Line 2, DL2) or a bone scan with CT (Diagnostic Line 3, DL3).
The study was divided into three phases: the standard protocols of the proposed imaging modalities DL1, DL2, and DL3 and analysis of scan times; estimation of energy consumption and emissions of DL1, DL2, and DL3; and collection of radiation dose data for imaging modalities (dose length production, DLP) and recording of contrast agent administration data for CT and radioactive tracers for bone scans and FDG-PET/CT exams.
In phase I, whole-body MRI was performed without contrast agents using T1-weighted and T2-weighted sagittal sequences for the spine, as well as axial T1-weighted, T2-weighted, and diffusion-weighted sequences from the head to mid-thigh. Images were acquired using a 1.5 tesla scanner (Magnetom Avanto, Siemens Healthineers) and processed both online and offline. Acquisition time was approximately 30 minutes, with the possibility of repeating suboptimal sequences due to motion artifacts or poor breathing control.
In phase II, patients underwent preliminary evaluations, including blood glucose analysis, before the FDG-PET/CT scan. The scan covered the orbitomeatal line to the midfemoral diaphysis using a PMT-based Discovery MI DR scanner PET/CT (General Electric) with a 3D technique. CT was performed using a spiral technique, low dose, and without contrast agents for attenuation correction and anatomical localization. The typical acquisition time was about 15 minutes, with additional scans required in cases of motion artifacts, bladder issues, or taller-than-average patients.
In phase III, the protocol involved multiple phases, including a baseline phase of the upper abdomen, an arterial phase of the upper abdomen, and a portal/venous phase covering the thorax, abdomen, and pelvis. Late-phase imaging was performed when clinically indicated for liver or kidney conditions. Scans were conducted using two CT systems (Somatom go.Top from Siemens).
Bone scintigraphy included anterior and posterior planar acquisitions performed using an NM-CT8E860 scanner (General Electric). SPECT and low-dose CT scans could be added for areas with suspected radiopharmaceutical uptake.
Masperi and Girlando conducted an analysis of the energy consumption and greenhouse gas emission per patient of all radiological equipment for diagnostic activities. Data on radiation doses and the administration of contrast agents or radiopharmaceuticals were also collected.
Total scan time was converted into hours to facilitate energy consumption and greenhouse gas emission calculations. Data were compared across individual imaging modalities and grouped diagnostic lines (DL1, DL2, DL3). Binary comparisons of scan times, energy consumption, and GHG emissions were conducted using the total scan time.
Main findings
A total of 70 patients (89.7%) were analyzed, while eight were excluded as their imaging was performed using different equipment and protocols. All patients participated in DL1, while DL2 (FDG PET/CT staging) involved 29/70 (41.4%) patients, and DL3 (staging with bone scan and CT) involved 41/70 (58.6%). As data on consumption and administration of contrast medium and radiopharmaceuticals were not available, it was decided to exclude these patients from the analysis.
The overall scan time varied significantly between diagnostic lines. DL2 had the shortest mean scan time (0.27 ± 0.04 hours), followed by DL1 (0.37 ± 0.05 hours), and DL3 (0.56 ± 0.04 hours). Within DL3, a bone scan required 0.35 ± 0.01 hours, while CT required 0.21 ± 0.03 hours (p < 0.05).
Summary diagram of average scan times for DL1, DL2 total, and individually for DL3 (bone scan and CT). All figures courtesy of Andrea Masperi and and Cristiano Michele Girlando presented at ECR 2025.
DL2 was the most energy-efficient, consuming 4.92 ± 0.81 kWh/patient, compared with 11.1 ± 1.72 kWh/patient for DL1 and 12.05 ± 1.65 kWh/patient for DL3. DL2 showed a 55% reduction in energy use and greenhouse gas emissions compared with DL1 (1443.03 vs. 3255.63 KgCO2e, p < 0.05). DL1 consumed 7% less energy and emitted 7% less greenhouse gas than DL3. Within DL2, bone scans consumed 3.11 ± 0.14 kWh/patient (912.16 KgCO2e), while CT scans consumed 8.93 ± 1.6 kWh/patient (2,619.16 KgCO2e).
Summary diagram of estimated imaging energy consumption for DL1, DL2 total, and individually for DL3 (bone scan and CT).
Radiation dose for FDG PET/CT included an average CT scan dose of 326.66 ± 45.08 mGy/cm and 241.71 ± 42 MBq of F-18 fluorodeoxyglucose. For bone scans, radiopharmaceutical injections averaged 693.87 ± 67.32 MBq. CT reported doses of 2,152.89 ± 340.62 mGy/cm and an average iodine contrast media volume of 114.72 ± 22 ml. The combined radiopharmaceutical dose for DL2 and DL3 was approximately 936 MBq/patient, while CT scans contributed a cumulative dose of around 2,480 mGy/cm.
The outcome was a reduction of electricity consumption and CO2 emissions by 55% per patient with DL2 vs DL1 and a reduction of electricity consumption and CO2 emissions by 7% per patient with DL1 vs DL3, Masperi and Girlando concluded.
"These results emphasize the importance of searching for the best and innovative diagnostic lines to balance diagnostic efficacy with energy and biological sustainability that can help not only radiology departments to become greener but also the patients who receive quality and sustainable care," they noted.
